Observation of thermomagnetically recorded domains with high-resolution magnetic soft x-ray microscopy

ABSTRACT Magnetic domains were thermomagnetically recorded on TbFeCo films using laser pulsed magnetic field modulation (LP-MFM) and light intensity modulation (LIM). The domains were observed with high resolution magnetic transmission X-ray microscopy (M-TXM) before and after the heat treatment in order to clarify the recordingcharacteristics and the thermal stability of recorded domains. From the results of M-TXM images, it was found thatisolated single marks whose lengths are much smaller than 100 nm can be recorded by LP-MFM but their mark lengthsbecome often longer than designed. It was further confirmed that the heat treatment at 120 degree C for 50 hours does notinfluence significantly the crescent-shaped magnetic domains of 100 nm in width recorded using LP-MFM method andcircular domains of 150 nm in diameter recorded using LIM method.Key words: magneto-optical recording, magnetic soft X-ray microscopy 1. INTRODUCTION The key issue to expand the fields of application for optical disks is to achieve high areal density. Fortunately, inmagneto-optical (MO) disk systems, it is possible to record smaller domains than the laser spot diameter. The recordingstrategies are roughly classified into two methods, light intensity modulation (LIM) and magnetic field modulation(MFM). Furthermore, as a modified method ofMFM, laser pulsed magnetic field modulation (LP-MFM) has beendeveloped to improve the recording quality .